Here’s some great posts on troubleshooting slow boot and slow logons:
- http://blogs.technet.com/b/markrussinovich/archive/2012/07/02/3506849.aspx
- http://blogs.technet.com/b/askpfeplat/archive/2012/06/09/slow-boot-slow-logon-sbsl-a-tool-called-xperf-and-links-you-need-to-read.aspx
- http://blogs.technet.com/b/markrussinovich/archive/2010/01/13/3305263.aspx
- http://blogs.technet.com/b/jeff_stokes/archive/2009/12/18/why-do-i-have-long-boot-times.aspx